Hydro-mechanical drive systems for combine rotors monitor a variety of system parameters when controlling the engagement, disengagement and speed of combine rotors. They typically have a variety of sensors responsive to pressures, speeds and positions of the various components comprising the systems.
Normally, system parameters, which are necessary for the control algorithms and the display of data to the operator, are measured directly by using sensors. For example, a sensor may directly indicate the gear ratio or range of the drive system's transmission. Other sensors may measure system hydraulic pressure, rotor speed, shaft speed, and other parameters.
Because of the limitations of these sensors, such as high cost, large size, and unreliability, it would be beneficial to eliminate one or more sensors to reduce the cost, reduce the size, and increase the reliability of the combine and its control systems.
The present invention provides a means to obtain the desired system parameters without the cost of the additional sensors, and in certain cases, obtain values for physical parameters that cannot otherwise be measured.
Since processing capability has increased tremendously in recent years, a micro-controller can run a system model (models, or equation(s)), called a system estimator, in real time along with the conventional control algorithms. The system estimator can combine one or more sensor values with a system model to estimate an operational parameter of the combine that would otherwise require a separate sensor, or would otherwise be immeasurable.
These estimated parameters can be used merely as information to the operator, such as by displaying them to the operator, or can be used to control various vehicle operations.
Although applicable to any system that can be modeled, a particular embodiment of a system estimator with applicability to a hydro-mechanical drive system on a combine is disclosed.